This invention is directed to surfactant materials and compositions and to methods for making concentrated intermediates with good handling properties.
Rheological behavior is an important consideration in a liquid. An appropriate viscosity in a liquid product enables it to either be (a) usefully consumed as received or (b) conveniently received into a conditioning system for further adjustment of the viscosity to a useful value for the application. The utility of components used in a liquid blend is also affected by viscosity; and, in this regard, highly concentrated alkyl diphenyl oxide sulfonic acid as manufactured has a relatively high liquid viscosity. DOWFAX(trademark) surfactants (DOWFAX is a trademark of The Dow Chemical Company) are good examples of products from alkyl diphenyl oxide sulfonic acids. Highly concentrated alkyl diphenyl oxide sulfonic acids have solids concentrations from about 60% to about 95% and are denoted as High Actives Acid, or HAA, herein. While the high viscosity can be moderated to acceptable levels with dilution in some HAAs, other HAAs (e.g. DOWFAX Detergent Acid) demonstrate an apparent liquid crystal region in the 40% to 80% solids range. The liquid crystal region is characterized by very high viscosity (greater than 1,000,000 centipoise) and the material is accordingly too viscous at temperatures below 40 degrees C. for convenient handling. When the material is heated to render the viscosity acceptably convenient, the material is unfortunately too hot for safe handling outside of relatively expensive blending environments optimized for safe operations at such temperatures. As noted previously, DOWFAX surfactants are good examples of products from alkyl diphenyl oxide sulfonic acids. DOWFAX surfactants have two ionic charges per molecule. Each molecule consists of a pair of sulfonate groups on a diphenyl oxide backbone. This double charge density is largely responsible for excellent solvating and coupling action in this molecular family. DOWFAX surfactants have excellent solubility and stability in concentrated electrolytes and are resistant to oxidative and thermal degradation. DOWFAX surfactants have hydrophobes of a linear or branched alkyl group comprised of from six to sixteen carbons, depending upon the particular surfactant. Example utility of DOWFAX surfactants is in textile dyeing, polymer emulsion processing, agricultural chemical manufacturing, and (as an additive) cleaning fluid formulating.
It has been desired for some time to be able to sell High Active Acid as a concentrated product for use in formulations prior to neutralization in order to minimize shipping and handling costs respective to the surfactant product water component; however, (a) the addition of water to HAA at room temperature has traditionally not been convenient because of the high viscosity of the HAA at room temperatures and (b) most customers for the surfactant product are not conveniently availed of a blending environment for safe handling of hot HAA. Speculated benefits, therefore, of efficiency in shipping and handling and the benefits in safety from an HAA which could be blended into water at room temperature have not been realized. What is needed is an HAA having a useful viscosity at room temperature which can be added to water. The present invention solves this problem by providing HAA formulation embodiments and methods for their formulation so that an HAA having a relatively low viscosity at room temperature is provided.
The room temperature viscosity of an alkyl diphenyl oxide sulfonic acid blend is beneficially controlled according to the invention by admixing a fatty acid having a carboxylic chain length between 1 and 12 into the alkyl diphenyl oxide sulfonic acid blend to provide between about 5 weight percentage and about 50 weight percentage of fatty acid in the admixture.